simpler implementation of backdoor.py

gevent/backdoor.py

-# @author Bob Ippolito
-#
-# Copyright (c) 2005-2006, Bob Ippolito
-# Copyright (c) 2007, Linden Research, Inc.
-# Copyright (c) 2008, Donovan Preston
-# Copyright (c) 2009-2010, Denis Bilenko
-# Copyright (c) 2011, gevent contributors
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in
-# all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-# THE SOFTWARE.
+# Copyright (c) 2009-2014, gevent contributors
+# Based on eventlet.backdoor Copyright (c) 2005-2006, Bob Ippolito
 
 from __future__ import print_function
 import sys
@@ -30,7 +7,7 @@ from code import InteractiveConsole
 
 from gevent import socket
 from gevent.greenlet import Greenlet
-from gevent.hub import PY3
+from gevent.hub import PY3, getcurrent
 from gevent.server import StreamServer
 
 __all__ = ['BackdoorServer']
@@ -45,58 +22,61 @@ except AttributeError:
     sys.ps2 = '... '
 
 
-class SocketConsole(Greenlet):
-
-    def __init__(self, locals, conn, banner=None):
-        Greenlet.__init__(self)
-        self.locals = locals
-        self.desc = _fileobject(conn)
-        self.banner = banner
-
-    def finalize(self):
-        self.desc = None
+class _Greenlet_stdreplace(Greenlet):
+    _fileobj = None
 
     def switch(self, *args, **kw):
-        self.saved = sys.stdin, sys.stderr, sys.stdout
-        sys.stdin = sys.stdout = sys.stderr = self.desc
+        if self._fileobj is not None:
+            self.switch_in()
         Greenlet.switch(self, *args, **kw)
 
+    def switch_in(self):
+        self.saved = sys.stdin, sys.stderr, sys.stdout
+        sys.stdin = sys.stdout = sys.stderr = self._fileobj
+
     def switch_out(self):
         sys.stdin, sys.stderr, sys.stdout = self.saved
+        self.saved = None
 
-    def _run(self):
+    def run(self):
         try:
-            try:
-                console = InteractiveConsole(self.locals)
-                # __builtins__ may either be the __builtin__ module or
-                # __builtin__.__dict__ in the latter case typing
-                # locals() at the backdoor prompt spews out lots of
-                # useless stuff
-                try:
-                    import __builtin__
-                    console.locals["__builtins__"] = __builtin__
-                except ImportError:
-                    import builtins
-                    console.locals["builtins"] = builtins
-                console.interact(banner=self.banner)
-            except SystemExit:  # raised by quit()
-                if not PY3:
-                    sys.exc_clear()
+            return Greenlet.run(self)
         finally:
+            # XXX why is this necessary?
             self.switch_out()
-            self.finalize()
 
 
 class BackdoorServer(StreamServer):
 
     def __init__(self, listener, locals=None, banner=None, **server_args):
-        StreamServer.__init__(self, listener, spawn=None, **server_args)
+        StreamServer.__init__(self, listener, spawn=_Greenlet_stdreplace.spawn, **server_args)
         self.locals = locals
         self.banner = banner
-        # QQQ passing pool instance as 'spawn' is not possible; should it be fixed?
+        self.stderr = sys.stderr
 
     def handle(self, conn, address):
-        SocketConsole.spawn(self.locals, conn, banner=self.banner)
+        f = getcurrent()._fileobj = _fileobject(conn)
+        f.stderr = self.stderr
+        getcurrent().switch_in()
+        try:
+            console = InteractiveConsole(self.locals)
+            # __builtins__ may either be the __builtin__ module or
+            # __builtin__.__dict__ in the latter case typing
+            # locals() at the backdoor prompt spews out lots of
+            # useless stuff
+            try:
+                import __builtin__
+                console.locals["__builtins__"] = __builtin__
+            except ImportError:
+                import builtins
+                console.locals["builtins"] = builtins
+            console.interact(banner=self.banner)
+        except SystemExit:  # raised by quit()
+            if not PY3:
+                sys.exc_clear()
+        finally:
+            conn.close()
+            f.close()
 
 
 class _fileobject(socket._fileobject):
@@ -118,4 +98,4 @@ if __name__ == '__main__':
     if not sys.argv[1:]:
         print('USAGE: %s PORT' % sys.argv[0])
     else:
-        BackdoorServer(('127.0.0.1', int(sys.argv[1]))).serve_forever()
+        BackdoorServer(('127.0.0.1', int(sys.argv[1])), locals={'hello': 'world'}).serve_forever()